Tread belt and assembly

ABSTRACT

An endless tread belt adapted to pass about two or more surface locomotion wheels is formed of an elastomeric material and has a plurality of spaced cleat portions extending generally transversely of the tread belt body; a generally medially situated constraining belt is contained generally within the belt body and positioned so as to have the medial portion thereof coextensive with the pitch diameter of the belt body, the constraining belt or strap is effective for assuring tracking means formed on the tread belt to be closely received within cooperating guide means formed in the surface locomotion wheels; the sides of the tread belt are provided with integrally formed passage-type locking means for receiving therein fingerlike locking members of side closure walls connectable to the tread belt at opposite sides thereof in order to form an enclosed chamber containing the locomotion wheels.

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Cushman et a1.

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[54] TREAT) BELT AND ASSEMBLY [72] Inventors: Walton W. Cushman, Fraser,Mich.; Martin Tucker, as trustee,New York, NY.

[22] Filed: Dec.4, 1969v [21] Appl.No.: 881,975

[52] US. Cl. ..305/35 EB, 305711, 305/20 [51] ..B62d 55/24 [58] Field ofSearch ..305/35 EB, 37, 38,56

[56] References Cited UNITED STATES PATENTS 2,592,541 4/1952 Curtis..305/38 X 2,652,290 9/1953 Bekker... 305/38 X 3,118,709 l/l964 Case.305/37 3,276,823 10/1966 Tucker... ....305/35 EB X 3,451,728 6/1969Braneau ..305/35 EB X FOREIGN PATENTS OR APPLICATIONS 584,226 1/1947GreatBritain ..305/38 1 Feb.l,l972

Primary ExaminerRichard J. Johnson Attorney-Ion H. Romanski [5 7]ABSTRACT An endless tread belt adapted to pass about two or more surfacelocomotion wheels is formed of an elastomeric material and has aplurality of spaced cleat portions extending generally transversely ofthe tread belt body; a generally medially situated constraining belt iscontained generally within the belt body and positioned so as to havethe medial portion thereof coextensive with the pitch diameter of thebelt body,

the constraining belt or strap is effective for assuring tracking meansformed on the tread belt to be closely received within cooperating guidemeans formed in the surface locomotion wheels; the sides of the treadbelt are provided with integrally formed passage-type locking means forreceiving therein fingerlike locking members of side closure wallsconnectable to the tread belt at opposite sides thereof in order to forman enclosed chamber containing the locomotion wheels.

15 Claims, 11 Drawing Figures PATENTED FEB H972 3.639.012

I N VliN TOR I ATTORNEY TREAD BELT AND ASSEMBLY BACKGROUND OF THEINVENTION Heretofore, various forms of tread belts have been proposed.However, such prior art tread belts have not always been satisfactorybecause of the undesirable effects that centrifugal forces create on thetread belt as such tread belt passes over and about cooperating surfacelocomotion wheels. This becomes especially important in situations wherethe belt body is relatively thin, and of elastomeric material, andrequired to undergo substantial surface velocities.

Additional problems have been encountered in those situations where atread belt, as above, was to be provided with side or end closure wallsconnected to the tread belt as by a mechanical interlocking of relatedcomponents formed by both the sidewalls and the tread belt. Becauseofsuch centrifugal forces, the interlocking elements were often causedto disengage thereby separating the sidewalls from the tread belt.

Accordingly, the invention as herein disclosed and described isconcerned with the solution of the above as well as other relatedproblems.

SUMMARY OF THE INVENTION According to the invention, a tread beltcomprises an endless tread belt body formed of an elastomeric materialand having inner and outer surfaces, a plurality of spaced cleat meansformed on and carried by said outer surface of said body, saidconstraining belt means being so situated as to have a midportionthereof substantially coextensive with the pitch line of said treadbelt.

Various objects and advantages of the invention will become apparentwhen reference is made to the following detailed description consideredin conjunction with the accompanying drawings.

DESCRIPTION OF THE DRAWINGS In the drawings, wherein for purposes ofclarity certain details may be eliminated from one or more views:

FIG. I is a vie illustrating, in perspective, a fragmentary portion of avehicle provided with a tread belt in accordance with the teachingsofthe invention;

FIG. 2 is an enlarged side elevational view of the fragmenta r v portionof the vehicle of FIG. 1, including the associated locomotion apparatus,with certain portions thereof broken away and in cross section andcertain other elements removed for purposes ofclarity;

FIG. 3 is a somewhat simplified perspective view of the tread belt andsidewalls in generally exploded position;

FIG. 4 is an enlarged fragmentary cross-sectional view taken generallyon the plane ofline 44 ofFIG. 3 and looking in the direction ofthearrows;

FIG. 5 is a fragmentary cross-sectional view taken generally on theplane ofline 55 of FIG. 4 and looking in the direction of the arrows;

FIG. 6 is an enlarged transverse cross-sectional view of the tread belttaken generally on the plane of line 6-6 of FIG. 3 and looking in thedirection of the arrows;

FIG. 7 is an enlarged fragmentary cross-sectional view taken generallyon the plane of line 77 of FIG. 3 with the related side wall securedthereto;

FIG. 8 is an enlarged fragmentary perspective view of a locking portionformed on the tread belt;

FIG. 9 is a fragmentary crosssectional view taken generally on the planeofline 9-9 of FIG. 7.

FIG. 10 is a view similar to FIG. 7 but illustrating a modified fromofthe invention; and

FIG. 11 is an enlarged cross-sectional view taken generally on the planeofline 11-11 of FIG. 3 including, for illustrative purposes. afragmentary portion of the related locomotion aparatus.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now in greater detailto the drawings, FIG. I illustrates, in perspective, a fragmentaryportion of a vehicle 10 having a seat portion 12 and an engine housing14 with, for example, a removable cover 16 within which is generallysituated suitable power conveying means such as a continuous belt orchain 18 (FIG. 2) which serves to convey driving power to a tracklikelocomotion apparatus 20 situated at the rear ofthe vehicle 10.

As generally illustrated in FIG. 2, the locomotion apparatus 20 may becomprised of spaced axially elongated wheels or rollers 22 and 24between which is situated a main load hub or roller 26 having itsopposite axial ends journaled within, for example, bearing portionscarried by the vehicle body 26 as typically shown at 28. A system ofcontinuous belts or chains may be employed for generally unifying thewheels 22 and 24 and roller 26 into an operational locomotion apparatus.For example, first load belt means 30 may be provided so as to generallycircumferentially encompass a major peripheral portion of each of thewheels 22 and 24 and have its lower run portion 32 generally tangent tothe lower portions of wheels 22 and 24 while the upper run portion 36 islooped as to pass under and in contact with the main or vehicle loadroller 26. Additional snubbing or tensioning belt means 38 may be provided so as to similarly circumferentially encompass a major peripheralportion of each of the wheels 22 and 24 and have its upper run portion40 generally tangent to the upper portions of wheels 22 and 24 while thelower run portion 42 thereof is looped as to pass over and in contactwith the main or vehicle load roller 26. As shown, the various beltmeans may be situated within suitable grooves formed in andcircumferentially about the wheels and hub.

An engine 44, having an output shaft 46, and a controllable powertransmission assembly 48 are operatively connected to the main loadroller 26 as by the belt or chain 18. Preferably, there would be such apower chain or belt disposed on each side of the vehicle 10 so as to beconnected to cooperating sheaves or sprockets 50 mounted on the hub 26externally beyond the axial ends of the cooperating wheels 22 and 24.

The locomotion apparatus 20 disclosed herein is merely by way of examplesince the-precise configuration thereof forms no part of this inventionexcept to the extent that it be one in which tread belt means can beemployed thereabouts as generally indicated at 52 of FIGS. 1 and 2.

FIG. 3, a generally exploded perspective view, illustrates the treadbelt means 52 as being comprised of an endless elastomeric (preferablyof polyurethane in the order of 60 Shore A) belt 54 which is adapted tobe mounted about, for example, the wheels 22 and 24 for coaction withoppositely disposed end walls 56 and 58 which, when connected to thebelt 54, serve to form a totally enclosed or sealed chamber containingthe wheels 22, 24 and hub 26. Preferably, the end walls or sealingmembers 56 and 58 are formed of a relatively softer elastomeric material(in the order of, for example, 30-35 Shore A).

FIG. 4, an enlarged fragmentary cross-sectional view taken generally onthe plane of line 4-4 of FIG. 3, illustrates the continuous or endlessbelt 54 as being comprised of a main body portion 60 with the outersurface thereof formed to provide a continuous band of cleats orcleatlike projections 62 extending generally transversely of the beltbody 60 so as to be situated generally between continuous bands 64 and66 of sidewalls locking means. Further, as is shown in each of FIGS.3,4,5 and 6, a continuous bandlike body portion 68 is formed integrallywith belt body 60 and cleat portions 62 so as to be disposed generallymedially of the tread belt 54.

As is illustrated in FIGS. 4 and 6, a plurality medially disposed andspaced belt tracking lugs 70 are formed integrally with medial bodyportion 68 in a manner so as to be disposed inwardly thereof. Thepurpose of having successive lugs 70 spaced from each other is toprovide sufficient room or space therebetween to accommodate therelative movement of such lugs 70 toward each other as the belt 54contacts the wheels 22 and 24 and follows the curvature thereof. Suchtracking or guide lugs 70 would be provided where the belt 54 were to beemployed in combination with locomotion wheels having a continuouscircumferential tracking groove as typi cally illustrated at 72 of FIG.6. As shown, groove 72 is ofa V- like cross-sectional configurationincluding sidewall surfaces 74 and 76 which are adapted to be confinedby groove sidewalls 78 and 80 in order to preclude undesirable lateralmovement ofthe guide lugs 70 and therefore the belt body 60.

FIG. 6 also typically illustrates another feature of the invention, thatbeing, the provision of a holddown or constraining belt or wire 82carried by the tread belt 54. As can be seen, body portion 68 is formedto provide an opening or chamber 84 through the belt body 60 and each ofthe integrally formed tracking lugs 70. When the tread belt body 60 isheld against and passed about the locomotion wheels, as by having theinner surface 86 of belt body 60 against the outermost rolling diameter88 of the wheels, such as wheel 22, a plane, depicted generally by line89, exits within the belt body 60 which is neutral in that the plane orline 89 experiences neither compressive forces nor tension forcesarising out of the belt body rollingly deflecting about the wheels. Sucha plane or line 89, defined as the pitch line of the tread belt body,will be located generally midway between inner belt body surface 86 andouter belt body surface 106. Accordingly, chamber or opening 84 is soformed as to have the constraining strap 82 situated therein in a mannerplacing its midpoint or pitch line, as represented by line 90, to besubstantially coplanar with the pitch line 89. By so doing, suchcompressive forces as may be developed in the lower or inner half of thestrap 82, as the belt 54 passes about a cooperating locomotion wheel,are offset or counteracted by like and oppositely directed tensionforces developed in the upper or outer half of the constraining strap82. (The terms upper, and, lower, are employed with reference to thepitch line 90 passing through belt 82 as shown in FIGv 6.)

The purpose ofthe constraining strap 82 is to assure that the trackingor guide lugs 70 will be closely received within the cooperating guidegrooves, such as 72, formed within the cooperating locomotion wheels.

As is best shown in FIGS. 4 and 5, the upper surface 92 of the openingor passage 84 is formed as to be continuous, even as between succeedinglugs 70, while the lower surface 94 of the passage 84 extends onlythrough the individual succeeding guide lugs 70. Therefore, theconstraining or holding strap 82, shown in phantom line, has the lowerportion thereof exposed in the span of the tread belt body 60 generallybetween such succeeding guide lugs 70.

The constraining strap 82 may, of course, be made from any of a greatnumber of suitable materials, however, in the preferred form oftheinvention the strap 82 would be formed of woven nylon thereby impartinga high degree of flexibility to the strap 82 while still retaining theability to withstand high tensile forces.

Each of the end walls or sealing members 56 and 58 are illustrated asbeing comprised of a relatively thin-walled circular body portion 96,having a diameter substantially equal to the diameter of the locomotionwheels 22 and 24, with a plurality of generally radiating fingerportions or members 98 formed thereabout. In situations wherein the axisof the main drive hub 26 is to project through both sides ofthelocomotion apparatus 20, each ofthe walls or closures 56 and 58 would beprovided with an aperture 100 formed through and centrally ofthecircular body portion 96.

In the preferred form, each of the side closure walls, as typicallyillustrated by side wall 58 in FIG. 11, would have their circular body96 formed in a generally bellowslike configuration having a plurality ofgenerally concentric convolutions 102 and of progressively increasingdiameter from the center of the body 96.

Preferably, as best shown in FIG. 11, the sidewall body 96 is alsoprovided with a continuous cuplike wall portion 104 formed as to beaxially directed with respect to the general plane of body 96 and havingan effective length indicated generally by the dimension, X, in FIG. II.The length, X, as well as the relatively thickened cross section ofportion 104 is provided in order to accommodate the distance, X of FIG.6 as well as the distance from the outer surface 106 of tread belt body60 to the top surface 108 of beltlike portion 66. (The same, of course,applies to the other sidewall 56 and its application to the other sideof the tread belt 54.) Additionally, the sidewalls would preferably bemolded so as to have the finger portions 98 projecting generallyinwardly (the term, inward, being employed with reference to the side ofthe closure wall at which the tread belt 54 would be connected).

Preferably, the control portion of the sidewalls would be of increasedcross-sectional thickness, as shown at 110, through which would beformed the aperture 100. Such an aperture could then accommodate,therein, a suitable flanged backing or bearing member 112 which in turnwould permit the passage therethrough of a shaft portion 114 of the mainor vehicle load hub 26.

As shown in FIGS. 3, 6, 7, 8 and 9, the beltlike portions 64 and 66 areformed continuously about the tread belt 54 so as to have the uppersurfaces 108 thereof at substantially the same height or level as theapexes 116 of the cleat portions 62. Further, in the preferred form,each ofthe beltlike portions 64 and 66 is provided with clearancepassageways 118 formed therethrough so as to be generally transverse ofthe tread belt 54 and to be in alignment with the trough or spacesbetween successive cleats 62. As best shown in FIGS. 8 and 9, the lowersurface 120 of each of the passageways 118 is of arcuate crosssectionalconfiguration which is effectively an extension or continuation of thearcuate space between succeeding cleats 62. However, as is shown inFIGS. 6, 7 and 10, the upper surface 122 of each of the passageways 118is generally flat (when viewed as in FIG. 8) but tapered when viewed inlongitudinal cross section so as to present an outer opening I24somewhat larger than the inner opening 126.

As shown in FIGS. 7, 9, 10 and 11, the finger portions 98 are eachcomprised ofa relatively elongated body portion 128 terminating at oneend at a shoulder 130, formed on the cuplike annular portion 104, andterminating at the free end in an elongated lead portion 132 which isprovided with an abutment portion or surface 134. As viewed in FIG 9, itcan be seen that each ofthe fingers 98 is preferably formed as to have atransverse cross-sectional configuration closely approximating thecontour of the passage means 118.

When the side closures 56 and 58 are to be used, they may be assembledin the following manner. After the tread belt 54 is assembled onto thelocomotion wheels 22 and 24, the sidewalls, such as 58, are brought upagainst the generally open axial end of the locomotion apparatus 20 andthe bearing or sleeve 112 is slipped onto shaft 114 of the vehicle ormain load hub 26. Next, each of the fingers 98 is inserted into anddrawn through a cooperating passageway 118. Being of an elastomericmaterial, the main body portion 128 of the finger portions 98 may besomewhat stretched so as to have the lead end 132 pulled through thepassageway 118 until the abutment portion 134 is free to abut againstthe inner abutment surface 136 thereby causing the outer abutmentsurface 138 of, for example, belt 66 to abuttingly engage the shoulder130. Once all the finger members 98 are so drawn through cooperatingpassages 118, the sidewall is secured to the tread belt 54.

Preferably, the width of the tread belt 54 would be such as to extendsome distance beyond the axial ends of the locomotion wheels 22 and 24.As typically illustrated in FIG. 7, this would result in the innersurface 140 of sidewall 58 being maintained some distance away from end142 of the wheel 22 thereby preventing rubbing between such surfaces.

FIG. 10 illustrates a modification of both the tread belt 54 and thesidewall as 58. All elements which are like or similar to those of thepreceding figures are identified with like reference numbers. Astypically illustrated, each side of the tread belt 54 is formed with acontinuous bead 144 which is adapted to be closely received within acooperating continuous groove 146 formed in the body 96 of a sidewall,such as 58, generally at the corner formed by the cuplike wall portion104. Further, preferably, the inner surface of the tread belt 54 isformed as to be somewhat curved inwardly as shown at 148, at the endthereof; the curved portion 148 being provided to cooperate with a likecurved portion formed as on the locomotion wheel 22. As is evident, inview of FIG. 10, the curved portion 148 also serves to maintain anoperational clearance between surfaces 140 and 142 of the sidewall body96 and locomotion wheel 22.

As was previously stated, the effective diameter of the sidewalls, asgenerally represented by the dimension, D, of FIG. 11, is in its freestate generally equal to the outer diameter the locomotion wheels 22 and24 and therefore, when applied there would be no substantial stretchingof the sidewalls when measured vertically through the axle 114 of FIG.2. However, it should also be evident that such applied sidewall will bestretched a maximum distance when measured generally horizontallythrough the same axle 114 of FIG. 2.

Accordingly, it can be seen that when the tread belt 54 is employed incombination with the side closures and the locomotion wheels are rotatedcausing the tread belt to pass around such wheels, the sidewalls willcontinually undergo varying degrees of stretching to each side of a linedrawn vertically through the hub shaft 114 as viewed in FIG. 2. However,such stretching is greatly accommodated by the convolutions 102 whichpermit multidirectional stretching or relative movement of the sidewallbody 96.

It is, of course, conceivable that the tread belt 54 could be employedwith or without the sidewalls 56 and 58 in combination therewith.Further, it should be apparent, in view of the preceding disclosure,that it would be possible to employ a tread belt such as 54 without thetracking means 70 when such tread belt was to be employed in combinationwith sidewall closures such as 56 and 58. In such instance, thecooperating sidewalls could provide the degree of tacking controlnecessary for assuring the proper tracking of the tread belt about thelocomotion wheels.

Although the cleats 62 of the tread 54 could be of differentcross-sectional configuration, the preferred configuration is that asshown. Various benefits are derived by use of such a preferredconfiguration. For example, by providing a greater number of groovesbetween such cleat portions a more uniform bending of the belt isachieved as it passes about the locomotion wheels. Further, inconstructing the belt 54 with cleats as shown, a substantial savings inmanufacturing costs can be achieved by the employment of commerciallyavailable half-rounds(elongated rods which have one cylindrical surfaceand a second flat surface corresponding to the diameter of such acylinder) within the mold assembly for molding the tread belt.

In addition to the above, it should be apparent that the inventionprovides means for overcoming the effects of centrifugal force, on atotally enclosing tread belt assembly, which might otherwise result inthe disengagement between the tread belt and sidewalls connectedthereto. That is, regardless of the centrifugal force experienced, thebandlike portions 64 and 66 prevent the finger portions 98 being thrownoutwardly and if there is any such tendency it would only have theeffect of causing the lead portion 132 more tightly engage the abutmentor looking surfaces 136.

Further, if desired, suitable inlet valve means 150 may be carried byone of the sidewalls, as 58 of FIG. 3, in order to enable the enclosedchamber defined by the tread belt assembly 52 to be at least partiallypressurized as by the application of air under pressure through theinlet valve means 150.

Although only a select number of embodiments of the invention have beendisclosed and described, it is apparent that other embodiments andmodifications of the invention are possible within the scope of theappended claims.

I claim:

l. A tread belt, comprising an endless tread belt body formed of anelastomeric material and having first innner and outer surfaces, saidtread belt being adapted to be so positioned with respect to associatedlocomotion wheels operationally carrying said tread belt as to have saidfirst inner surface of said tread belt held against an outer cylindricalsurface of said associated locomotion wheels, a plurality of cleat meansformed on and carried by said first outer surface of said body, andrelatively narrow constraining belt means carried by said tread beltbody generally medially of the sides of said tread belt body and spaceda substantial distance inwardly from said sides, said constraining beltmeans having second inner and outer surfaces and being so situated as tohave said second outer surface thereof within said tread belt body so asto be outwardly of said first inner surface of said tread belt bodywhile said second inner surface is situated generally radially inwardlyof said first inner surface of said tread belt body so as to therebyhave a generally continuous midportion of said constraining belt meanssubstantially coextensive with the pitch line of said tread belt body.

2. A tread belt, comprising an endless tread belt body formed of anelastomeric material and having inner and outer surfaces, a plurality ofspaced cleat means formed on and carried by said outer surface of saidbody, relatively narrow constraining belt means carried by said treadbelt body generally medially of the sides of said tread belt body andspaced a substantial distance inwardly from said sides, saidconstraining belt means being so situated as to have a continuousmidportion thereof substantially coextensive with the pitch line of saidtread belt, and belt-tracking means formed on and carried by said innersurface of said tread belt body, said constraining belt means beinglocated generally between said tracking means and said outer surface,said constraining belt means thereby being effective to apply its fullconstraining effect for constraining movement of said tread belt body inorder to thereby assure said belt tracking means to be confininglyreceived within guide means formed on associated locomotion wheelsoperationally carrying said tread belt body.

3. A tread belt, comprising an endless tread belt body formed of anelastomeric material and having inner and outer surfaces, a plurality ofspaced cleat means formed on and carried by said outer surface of saidbody, and relatively narrow constraining belt means carried by saidtread belt body generally medially of the sides of said tread belt bodyand spaced a substantial distance inwardly from said sides, saidconstraining belt means being so situated as to have a continuousmidportion thereof substantially coextensive with the pitch line of saidtread belt, said cleat means comprising a plurality of generally spacedoutwardly directed narrow apexlike ridges extending generallytransversely of said tread belt body, said ridges having spacestherebetween of a configuration generally semicylindrical cross section,said spaces being located from each other a distance as to causeadjoining ones of said semicylindrical cross sections generally to blendand meet each other at their widest most portions thereby defining saidnarrow apexlike ridges.

4. A tread belt, comprising an endless tread belt body formed of anelastomeric material and having inner and outer surfaces, a plurality ofspaced cleat means formed on and carried by said outer surface of saidbody, constraining belt means carried by said tread belt body, saidconstraining belt means being so situated as to have a midportionthereof substantially coextensive with the pitch line of said treadbelt, first and second continuous bandlike portions formed generally onand carried by said outer surface of said tread belt body, said firstand second continuous bandlike portions being respectively formed atleast near opposite sides of said tread belt body, passage means formedgenerally transversely of and through said continuous bandlike portions,first and second generally circular sidewall members for effectivelyclosing the opposite sides of said tread belt body when said tread beltbody is looped about associated surface locomotion wheels, each of saidsidewall members comprising a plurality of generally radiating fingerportions, each of said finger portions being adapted to be closelyreceived through said passage means in order to thereby draw saidsidewall members respectively into close assembled relationship to saidopposite sides of said tread belt body, and looking means effective formechanically locking said finger portions in said passage means.

5. A tread belt according to claim 4, wherein said first and secondsidewall members are formed of an elastomeric material,

6. A tread belt according to claim 4, wherein each of said circularsidewall members comprises a generally circular main body portion, andconvoluted expansion means formed integrally in said circular main bodyportion, said convoluted expansion means being effective to permitrelative movement of sections of said circular main body portion so asto cause effective extension and contraction of said circular main bodyportion as said tread belt body moves in a generally looped conditionabout said associated surface locomotion wheels.

7. A tread belt according to claim 4, wherein each of said circularsidewall members comprises a generally circular main body portion formedof an elastomeric material, and expansion means formed integrally insaid circular main body portion, said expansion means comprising aplurality of generally concentric annular convolutions of increasingdiameter with respect to the center of said circular main body portion.

8, A tread belt according to claim 4, wherein each of said circularsidewall members comprises a generally circular main body portion formedof an elastomeric material, and wherein each of said circular main bodyportions is in its free state ofa diameter closely approximating therolling diameter of said associated surface locomotion wheels.

9. A tread belt according to claim 4, wherein said plurality ofradiating finger portions are ofelastomeric material formed integrallyin each of said sidewall members, and wherein said locking meanscomprises an abutment portion formed on an end of each of said fingerportions and an abutment surface formed on each of said continuousbandlike portions, said abutment portions and said abutment surfacesbeing adapted to abuttingly engage each other in locking fashion asrespective ones of said finger portions are drawn through cooperatingones of said passage means formed through said continuous bandlikeportions.

10. A tread bclt according to claim 4, wherein each of said circularsidewall members comprises a generally circular main body section and acontinuous generally cuplike wall extension formed generallyperipherally about said main body section integrally therewith, whereinsaid plurality of radiating finger portions are formed integrally withsaid cuplike wall extension, and wherein said cuplike wall extension isheld on overlying relationship to said outer surface of said tread beltbody when said finger portions are drawn through said passage meansformed through said continuous bandlike portions.

11. A tread belt according to claim 4, wherein said cuplike wallextension is ofa cross-sectional thickness greater than thecross-sectional thickness of said generally circular main body section,including a continuous first abutment surface formed on said cuplikewall extension in the vicinity of thejuncture of said finger portionsand said cuplike wall extension, a second abutment surface formed on theouter end of said bandlike portions, wherein said locking meanscomprises an abutment portion formed on an end of each of said fingerportions and a third abutment surface formed on the inner end of saidbandlike portions, said first and second abutment surfaces being adaptedto abuttingly engage each other whenever respective ones of said fingerportions are drawn through cooperating ones of said passage means formedthrough said continuous bandlike portions so as to have said abutmentportion abuttingly engage said third abutment surface.

12. A tread belt according to claim 4, wherein said tread belt body isprovided with an integrally formed continuous bead formed at each sideof said tread belt body, and wherein each of said sidewall members isprovided with an integrally formed circular groove, each of said beadsbeing adapted for reception in respective ones of said grooves when saidsidewalls are assembled to said tread belt.

13. A tread belt, comprising an endless tread belt body formed of anelastomeric material and having inner and outer surfaces, a plurality ofspaced cleat means formed on and carried by said outer surface of saidbody, constraining belt means carried by said tread belt body, saidconstraining belt means being so situated as to have a midportionthereof substantially coextensive with the pitch line of said treadbelt, first and second continuous bandlike portions formed generally onand carried by said outer surface of said tread belt body, said firstand second continuous bandlike portions being respectively formed atleast near opposite sides of said tread belt body, said cleat meanscomprising a plurality of generally spaced outwardly directed ridgesextending generally transversely of said tread belt body between saidfirst and second continuous bandlike portions, passage means formedgenerally transversely of and through said continuous bandlike portions,first and second generally circular sidewall members for effectivelyclosing the opposite sides of said tread belt body when said tread beltbody is looped about associated surface locomotion wheels, each of saidsidewall members comprising a plurality of generally radiating fingerportions, each of said finger portions being adapted to be closelyreceived through said passage means in order to thereby draw saidsidewall members respectively into close assembled relationship to saidopposite sides of said tread belt body, and locking means effective formechanically locking said finger portions in said passage means.

14. A tread belt according to claim 13, wherein at least one of saidcircular sidewall members is provided with an aperture formedtherethrough generally centrally thereof, said aperture being effectivefor receiving therethrough a member of the locomotion apparatusgenerally confined by said tread belt and sidewall members.

15. A tread belt, comprising an endless tread belt body formed of anelastomeric material and having inner and outer surfaces, a plurality ofspaced cleat means formed on and carried by said outer surface of saidbody, relatively narrow constraining belt means carried by said treadbelt body generally medially of the sides of said tread belt body andspaced a sub stantial distance inwardly from said sides, saidconstraining belt means being so situated as to have a continuousmidportion thereof substantially coextensive with the pitch line of saidtread belt, and tread belt tracking means formed on and carried by saidinner surface of said tread belt body, said tracking means comprising aplurality of inwardly extending tracking portions spaced from each otherlongitudinally of said tread belt body, said constraining belt meanscomprising an outermost longitudinal extending surface and an innermostlongitudinally extending surface, said constraining belt means beingreceived through passage means formed in said tread belt body in amanner as to have said outermost longitudinal extending surfacecontinuously juxtaposed to said tread belt body while said innermostlongitudinally extending surface is totally exposed between said spacedtracking portions.

1. A tread belt, comprising an endless tread belt body formed of anelastomeric material and having first innner and outer surfaces, saidtread belt being adapted to be so positioned with respect to associatedlocomotion wheels operationally carrying said tread belt as to have saidfirst inner surface of said tread belt held against an outer cylindricalsurface of said associated locomotion wheels, a plurality of cleat meansformed on and carried by said first outer surface of said body, andrelatively narrow constraining belt means carried by said tread beltbody generally medially of the sides of said tread belt body and spaceda substantial distance inwardly from said sides, said constraining beltmeans having second inner and outer surfaces and being so situated as tohave said second outer surface thereof within said tread belt body so asto be outwardly of said first inner surface of said tread belt bodywhile said second inner surface is situated generally radially inwardlyof said first inner surface of said tread belt body so as to therebyhave a generally continuous midportion of said constraining belt meanssubstantially coextensive with the pitch line of said tread belt body.2. A tread belt, comprising an endless tread belt body formed of anelastomeric material and having inner and outer surfaces, a plurality ofspaced cleat means formed on and carried by said outer surface of saidbody, relatively narrow constraining belt means carried by said treadbelt body generally medially of the sides of said tread belt body andspaced a substantial distance inwardly from said sides, saidconstraining belt means being so situated as to have a continuousmidportion thereof substantially coextensive with the pitch line of saidtread belt, and belt-tracking means formed on and carried by said innersurface of said tread belt body, said constraining belt means beinglocated generally between said tracking means and said outer surface,said constraining belt means thereby being effective to apply its fullconstraining effect for constraining movement of said tread belt body inorder to thereby assure said belt tracking means to be confininglyreceived within guide means formed on associated locomotion wheelsoperationally carrying said tread belt body.
 3. A tread belt, comprisingan endless tread belt body formed of an elastomeric material and havinginner and outer surfaces, a plurality of spaced cleat means formed onand carried by said outer surface of said body, and relatively narrowconstraining belt means carried by said tread belt body generallymedially of the sides of said tread belt body and spaced a substantialdistance inwardly from said sides, said constraining belt means being sosituated as to have a continuous midportion thereof substantiallycoextensive with the pitch line of said tread belt, said cleat meanscomprising a plurality of generally spaced outwardly directed narrowapexlike ridges extending generally transversely of said tread beltbody, said ridges having spaces therebetween of a configurationgenerally semicylindrical cross section, said spaces being located fromeach other a distance as to cause adjoining ones of said semicylindricalcross sections generally to blend and meet each other at their widestmost portions thereby defining said narrow apexlike ridges.
 4. A treadbelt, comprising an endless tread belt body formed of an elastomericmaterial and having inner and outer surfaces, a plurality of spacedcleat means formed on and carried by said outer surface of said body,constraining belt means carried by said tread belt body, saidconstraining belt means being so situated as to have a midportionthereof substantially coextensive with the pitch line of said treadbelt, first and second continuous bandlike portions formed generally onand carried by said outer surface of said tread belt body, said firstand second continuous bandlike portions being respectively formed atleast near opposite sides of said tread belt body, passage means formedgenerally transversely of and through said continuous bandlike portions,first and second generally circular sidewall members for effectivelyclosing the opposite sides of said tread belt body when said tread beltbody is looped about associated surface locomotion wheels, each of saidsidewall members comprising a plurality of generally radiating fingerportions, each of said finger portions being adapted to be closelyreceived through said passage means in order to thereby draw saidsidewall members respectively into close assembled relationship to saidopposite sides of said tread belt body, and looking means effective formechanically locking said finger portions in said passage means.
 5. Atread belt according to claim 4, wherein said first and second sidewallmembers are formed of an elastomeric material.
 6. A tread belt accordingto claim 4, wherein each of said circular sidewall members comprises agenerally circular main body portion, and convoluted expansion meansformed integrally in said circular main body portion, said convolutedexpansion means being effective to permit relative movement of sectionsof said circular main body portion so as to cause effective extensionand contraction of said circular main body portion as said tread beltbody moves in a generally looped condition about said associated surfacelocomotion wheels.
 7. A tread belt according to claim 4, wherein each ofsaid circular sidewall members comprises a generally circular main bodyportion formed of an elastomeric material, and expansion means formedintegrally in said circular main body portion, said expansion meanscomprising a plurality of generally concentric annular convolutions ofincreasing diameter with respect to the center of said circular mainbody portion.
 8. A tread belt according to claim 4, wherein each of saidcircular sidewall members comprises a generally circular main bodyportion formed of an elastomeric material, and wherein each of saidcircular main body portions is in its free state of a diameter closelyapproximating the rolling diameter of said associated surface locomotionwheels.
 9. A tread belt according to claim 4, wherein said plurality ofradiating finger portions are of elastomeric material formed integrallyin each of said sidewall members, and wherein said locking meanscomprises an abutment portion formed on an end of each of said fingerportions and an abutment surface formed on each of said continuousbandlike portions, said abutment portions and said abutment surfacesbeing adapted to abuttingly engage each other in locking fashion asrespective ones of said finger portions are drawn through cooperatingones of said passage means formed through said continuous bandlikeportions.
 10. A tread belt according to claim 4, wherein each of saidcircular sidewall members comprises a generally circular main bodysection and a continuous generally cuplike wall extension formedgenerally peripherally about said main body section integrallytherewith, wherein said plurality of radiating finger portions areformed integrally with said cuplike wall extension, and wherein saidcuplike wall extension is held on overlying relationship to said outersurface of said tread belt body when said finger portions are drawnthrough said passage means formed through said continuous bandlikeportions.
 11. A tread belt according to claim 4, wherein said cuplikewall extension is of a cross-sectional thickness greater than thecross-sectional thickness of said generally circular main body section,including a continuous first abutment surface formed on said cuplikewall extension in the vicinity of the juncture of said finger portionsand said cuplike wall extension, a second abutment surface formed on theouter end of said bandlike portions, wherein said locking meanscomprises an abutment portion formed on an end of each of said fingerportions and a third abutment surface formed on the inner end of saidbandlike portions, said first and second abutment surfaces being adaptedto abuttingly engage each other whenever respective ones of said fingerportions are drawn through cooperating ones of said passage means formedthrough said continuous bandlike portions so as to have said abutmentportion abuttingly engage said third abutment surface.
 12. A tread beltaccording to claim 4, wherein said tread belt body is provided with anintegrally formed continuous bead formed at each side of said tread beltbody, and wherein each of said sidewall members is provided with anintegrally formed circular groove, each of said beads being adapted forreception in respective ones of said grooves when said sidewalls areassembled to said tread belt.
 13. A tread belt, comprising an endlesstread belt body formed of an elastomeric material and having inner andouter surfaces, a plurality of spaced cleat means formed on and carriedby said outer surface of said body, constraining belt means carried bysaid tread belt body, said constraining belt means being so situated asto have a midportion thereof substantially coextensive with the pitchline of said tread belt, first and second continuous bandlike portionsformed generally on and carried by said outer surface of said tread beltbody, said first and second continuous bandlike portions beingrespectively formed at least near opposite sides of said tread beltbody, said cleat means comprising a plurality of generally spacedoutwardly directed ridges extending generally transversely of said treadbelt body between said first and second continuous bandlike portions,passage means formed generally transversely of and through saidcontinuous bandlike portions, first and second generally circularsidewall members for effectively closing the opposite sides of saidtread belt body when said tread belt body is looped about associatedsurface locomotion wheels, each of said sidewall members comprising aplurality of generally radiating finger portions, each of said fingerportions being adapted to be closely received thrOugh said passage meansin order to thereby draw said sidewall members respectively into closeassembled relationship to said opposite sides of said tread belt body,and locking means effective for mechanically locking said fingerportions in said passage means.
 14. A tread belt according to claim 13,wherein at least one of said circular sidewall members is provided withan aperture formed therethrough generally centrally thereof, saidaperture being effective for receiving therethrough a member of thelocomotion apparatus generally confined by said tread belt and sidewallmembers.
 15. A tread belt, comprising an endless tread belt body formedof an elastomeric material and having inner and outer surfaces, aplurality of spaced cleat means formed on and carried by said outersurface of said body, relatively narrow constraining belt means carriedby said tread belt body generally medially of the sides of said treadbelt body and spaced a substantial distance inwardly from said sides,said constraining belt means being so situated as to have a continuousmidportion thereof substantially coextensive with the pitch line of saidtread belt, and tread belt tracking means formed on and carried by saidinner surface of said tread belt body, said tracking means comprising aplurality of inwardly extending tracking portions spaced from each otherlongitudinally of said tread belt body, said constraining belt meanscomprising an outermost longitudinal extending surface and an innermostlongitudinally extending surface, said constraining belt means beingreceived through passage means formed in said tread belt body in amanner as to have said outermost longitudinal extending surfacecontinuously juxtaposed to said tread belt body while said innermostlongitudinally extending surface is totally exposed between said spacedtracking portions.